Valve-gear for steam-engines



7 (No Model.) 3 Sheets-Sheet 1.

. "W. A; PITT. VALVE GEAR FOR STEAM 'fiNGINEgf 7 No. 546,056. PatentedSept. 10,- 1896'.

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(No Mode l.) I 3 Sheets-Sheet"2. W. A. PITT. VALVE GEAR FOR STEAMENGINES.

Patented Sept. 10,1895.

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' W. A. PITT.

VALVE GEAR FOR STEAM ENGINES.

Patented Sept. 10, 1895.;

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Attorney.

AN DREW BGRAHAM. FHOT0-UTI10.WASNINGTON llC.

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WILLIAM A. PITT, OF MANHASSET, NEW YORK.

VALVE-GEAR- FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 546,056, datedSeptember 10, 1895..

Application filed May '7, 1895. serial No. 548,407. (No model.)

To aZZ whom it may concern.-

Be itknown that 1, WILLIAM A. Prrr, a citizen of the United States,residing at Manhasset, in the county of Queens and State of New York,have invented certain new and useful Improvements in Valve-Gears forSteam- Engines, of which the following is a specification.

My invention relates to valve gears for steam-engines of the class towhich the engine described in my pending application, Serial No.540,952, belongs. In that form of engine four cylinders arranged inpairs are grouped about the main engine-shaft and the pistons thereofact in successive quadrants of the circle to impart continuous rotationto the shaft. The four valves which control the induction and exhaustports of the cylinders are actuated by cams on the main shaft.

The object of the present invention is to provide the engine withreversing mechanism and with a governor for automatically regulating theoperation of the valves.

In the accompanying drawings, which illustrate an embodiment of myinvention, Figure 1 is horizontal section of the engine and gear in theplane of the main shaft. Fig. 2 is a rear elevation of the same as seenfrom arrow y in Fig. 1. Fig. 3 is a vertical section of the engine,taken in the axes of the cylinders. Fig. 4 is a vertical section on linex m in Fig. 1. Fig. 5 is a face view of the valves and theiroperating-cams. Fig. 6 is a plan view of the engine provided with thereversing mechanism only. Fig. 7 is a view of the'valve-gear without thereversing mechanism.

1 represents the body of the engine; 2, the cylinders 3, the pistonstherein; 4, the pistonrods, those of each pair of pistons being rigidlyconnected to a yoke 5, which yokes act on equilateral triangular cams 6on the main shaft 7. At the back of the engine-body is the valve-chestor steam-chest 8, from which induction-ports 9 lead to the outer ends ofthe cylinders and exhaust-ports open into a circular passage 10, leadingto an exhaust outlet 11, Fig. 5. The steam is admitted to thesteam-chest by asupply-pipe 12, arranged in any way desired. The steaminduction and eduction ports are controlled by slidevalves 13, actuatedby a cam or cams on the main shaft 7.

disk or carrier 19..

So far as above described the construction is the same, or substantiallythe same, as that described and illustrated in my before-mentionedpending application; but in that. ap-

plication no devices were shown for reversing the engine, and nogovernor-controlled devices for shifting the cams were shown. These 1show herein.

The slide-valves 13, Fig. 5, are mounted in guides 14, and those of eachpair of oppositely-arranged valves are coupled to a yoke 15 in a mannersimilar to the pistons of the engine, and in each yoke is an equilateraltriangular cam 16. The cams 16 are both fixed to asleeve 17 on theprolongation of the main shaft 7, Fig. 1, and on the outer end of saidsleeve, exterior to the valve-chest, is fixed a gear-wheellS. (Seen inFigs. 1 and 4.) The shaft 7 projects out beyond the end of the sleeve 17and has mounted loosely on it a Beyond said disk and fixed on the shaft7 is a flanged boss 20, having in its flange a hole to receive a pin 21,the tip of which is adapted to enter one or more holes 22 in the carrier19. The wheel 18 is in gear with two wheels 23, rotatively mounted inthe carrier 19, through two intermediate wheels 24, also rotativelymounted on the carrier. The arbors23", on which the respective wheels 23are fixed, project out through the carrier, and on the outer ends ofsaid arbors are secured weighted arms 25, which operate in a mannersimilar to thearms and balls of a governor. On each arbor 23 is a stificoilspring 26, one end of which is secured to the arm 25 and the otherend to a bracket 27 on the carrier19.

The operation of the governor is as follows: The pin 21 fixes thecarrier 19 to the main shaft 7, and whe'rT'fhe latter rotates thecarrier moves with it. The engagement of the teeth of the wheel 18 onthe sleeve of the cams 16 with those of the wheels on the carrier causesthe carrier to drive the cams 16; but when the speed of the shaftreaches a velocity at which the centrifugal force, acting on theweighted arms 25, suffices to overcome the tension of the springs 26,the free ends of the arms move out radially, thus rotating the wheels 23to a moderate extentand through them the wheel 18, so as to shift thecams 16 about the main shaft, and thus modify their action on thevalves. The purpose of the intermediate wheels 24: is to cause thecarrier to drive the cam-sleeve with the main shaft and avoid therolling of the Wheels 23 about the wheel 18, which would result from theconcentric arrangement if the said wheels 23 geared directly with thecentral wheel. The purpose in employing two weighted arms and two setsof intermediate gears is merely to balance the construction. One arm andits appurtenances are merely a duplicate of the oth er. By withdrawingthe pin 21, turning the carrier 19 half-way around, and then againlocking the parts together with the pin the engine will be reversed. Inturning the carrier around, as described, the cams 16 will be carriedaround with it.

Fig. 6 illustrates a construction wherein only the reversing mechanismis employed. In this construction the governor mechanism is omitted, anda disk 19*, corresponding to the disk 19 of the principal views, issecured to the sleeve of the cams 16 and is adapted to be locked to theflanged boss by a pin.

Fig. 7 shows the disk or carrier 19 fixed to the main shaft directly bya set-screw, the mechanism for reversing previously shown being omittedfrom this view. It would be feasible, however, to reverse with thisconstruction by loosening the set-screw, turning the carrier half-wayaround on the shaft, and then driving the set-screw tight again. Thesprings 26 are of course designed to draw in the weighted arms when thespeed of the engine slackens. Any suitable adaptation of springs may beemployed for this purpose.

It will be noted that the cams'16 are arranged in yokes in the samemanner as the cams which are acted on by the pistons, and they will beset in line with the engine-cams on the shaft. Their positions areindicated by dotted lines in Fig. 3.

In Fig. 5 the cam-yokes are represented as connected to the respectivepairs of valves by rigid rods;

Having thus described my invention, I claim 1. In an engine havingcam-operated valves in a steam-chest and controlling the induction andeduction ports of the cylinders, the combination with the mainengine-shaft, of the valve-operating cam, mounted rotatively on saidshaft within the steam-chest and provided with a sleeve embracing theshaft and projecting therewith. from said chest, and means fordetachably connecting said sleeve and shaft exterior to the chest,substantially as set forth.

2. In an engine having cam-operated valves in a steam-chest andcontrolling the induction and eduction ports of the cylinders, the combination with the main engine-shaft, of the valve-operating cam, mountedrotatively on said shaft within the steam-chest and provided with asleeve embracing the shaft and projecting therewith from said chest, aflanged disk 20, fixed on the main shaft exterior to the steam-chest, adisk carried by said sleeve, adjacent to the disk 20, and a pin 21, toengage co-inciding holes in said disks and lock them together in theposition set, substantially as set forth.

3. In an engine having cam-operated valves in a steam-chest andcontrolling the induction and eduction ports of the cylinders, thecombination with the main engine-shaft, of the valve-operating cam,mounted rotatively on said shaft within the steam-chest and providedwith a sleeve embracing the shaft and projecting therewith from saidchest, a carrier-disk, on and fixed to the main shaft exterior to thesteam-chest, an arbor 23 mounted rotatively in said carrier-disk, agear-wheel 23, fixed on the said arbor, a weighted arm 25, also fixed onsaid arbor, a gear-wheel 18, fixed on the valve-sleeve adjacent to thecarrier-disk, an intermediate wheel, 24, in gear with both wheels 18 and23', and a spring adapted to act centripetally on the said weighted arm,substantially as and for the purposes set forth.

4. In an engine having four cylinders arranged about the main shaft, thecombination with the steam-chest, the main shaft extending out throughthe same, the four valves in said chest, said valves controlling theinduction and eduction ports of the several cylinders, the cam-yokescoupled to the respective valves, the two equilateral, triangular cams16, connected together and mounted rotatively on the main shaft, saidvalves having a sleeve 17, which embraces the shaft and extends out ofthe steam-chest, a gear-wheel 18, secured to the sleeve 17, exterior tothe steam-chest, a carrier-disk 19, secured to the main shaft adjacentto the gear-wheel 18, two arbors 23 rotatively mounted in saidcarrier-disk, gearwheels 23, and weighted arms 25, fixed on therespective arbors 23 wheels 24:, gearing with the respective wheels 18and 23, as set forth, and springs adapted to act centripetally on thesaid weighted arms, substantially as set forth.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

WILLIAM A. PITT. Witnesses:

PETER A. Ross, has KING DUFFY.

